Aerobic capacity is directly related to
a-flexibility
b-heart strength
c- bone strength
d-muscle endurance

i think either b or d

By definition we have to:

Aerobic capacity is the ability of the heart, blood vessels and lungs to function efficiently.

In this case, activities that require little effort and fatigue are carried out, but with rapid recovery.

Among the benefits we have:

1) Lose weight, by reducing body fat.

2) Improves cardiovascular function and lung capacity.

3) It helps to lower blood pressure and improve cholesterol levels.

According to the benefit number 2 mentioned above, the answer is:

B-heart strength

i think its pulmonary not sure tho